Blender camera with follow-path constraint does weird turns along curve
Path-following Camera -

Use a cube, either visible or invisible as the path object.
Add a line between two diagonally opposed corner vertices and subdivide that.
Set the cube's Origin point to that. (with SH-S)  (Shouldn't be necessary, but... )
Parent the camera to that vertice ONLY.  Select the cube, then the camera, go into Edit mode and select the center vertice.
Press CTL-P --&gt; 'Single Vertice' .
That will stop the cube's tilts &amp; rotation antics from affecting the camera.
The cam can also be turned and animated at will, or focus on some object or other using the 'Track-to' constraint.